Comparative Effects of Dexamethasone on Fetal

The importance of dexamethasone is demonstrated by its wide uses in human and veterinary medical practices [14]. Clinically, dexamethasone is administered to animals for the treatment of disease conditions such canine distemper, meningitis, necrotizing enterocolitis [5-10]. In humans, dexamethasone is most notably, used for the treatment of various complications, such as preterm complications to stimulate surfactant production by the lungs [3,11], intrahepatic cholestasis [12] and inflammatory conditions during pregnancy [13]. These actions are critical to prepare the fetuses for extrauterine life. Although this treatment greatly improves fetal and neonatal survival [3,14], they are not without adverse effects. Dexamethasone use has been associated with intra uterine fetal growth restriction (IUGR), decrease birth weight and placental weights in some animal models as well as humans [15-22]. The mechanisms underlying inhibitory effects of dexamethasone have largely not been elucidated. However, dexamethasone may probably exert its effect through fetal fluid medium. Amniotic and allantoic fluids protects the fetus by forming a protective physical cushion around it and allows the developing fetus to move freely inside the uterus and prevent teratogenicity due to adhesion and maintains an environment of constant temperature [23-25]. Fetal fluids are usually produced by placenta and other placentomes or fetal membrane during gestation until kidneys take over the task [23,24]. Other sources of fetal fluids include secretions from amniotic epithelium, fetal saliva, and nasopharyngeal secretions and skin, excretions of fetal kidneys and allantoic epithelia [26]. The biochemical constituents of amniotic fluid and allantoic usually provide valuable information for the assessment of fetal physiology and Abstract